Seems like on every forum everybody has the problem with the rough idle, hesitation and bucking under load. My truck did the same thing, I did all the usual stuff, intake gskts, numerous plugs and wires, fuel injector cleaner etc. the other day I was going to replace the plugs yet again but when I took them out they look like new. I am a motorcycle mechanic by trade and when we suspect a weak ignition we will gap the plugs down from the spec. If it runs better something is causing a weak ignition. And my truck runs good with fresh plugs for about a week and then acts up again. I gapped my plugs down .010" from spec and the truck runs better than ever. Before I could make it miss in gear with the brake on and on the throttle like a stall test, now I have no miss and the buck under light acceleration in overdrive at 40mph is gone. It is worth a try and I cant beleive how well it runs. Try it and post back.

 

Sounds like you've confirmed that you have a "weak" ignition system.

Steve

 

what do you do about the weak ignition? im new to this form can anyone tell me what this (cop) thing is? i have this same problem with my 99 xlt and it just happen when im barley on the gas doing between 30 and 50 mph. thanks for the help guys.

 

The V6 does not use COP - it uses standard coil packs and plug wires. COP = coil on plug.

 

thanks for the explaining that to me GLC. i took my truck to the shop and had them do the fuel system cleaning that cleans the injectors and the lines and so far my truck has not hesitated knock on wood, just to let u guys know that might help with you problems.

 

I dont think that it is a weak ignition. I was told by the ford dealer not to put platinum plugs in it. I think it takes less energy to fire a platinum plug than a regular plug. That is why when you put a fresh set of plugs in it will run good for a while, as soon as they get sooted up a bit it takes more energy to jump the gap and then it will start to misfire under acceleration in a high load low rpm situation. I gapped mine down about a month ago and it is still running excellent, rough start up is gone too! It is worth a try.